Efforts are continually being made to design compressors of smaller size. A smaller compressor may be achieved by employing a smaller impeller. However, a smaller impeller is required to rotate at higher speeds in order to achieve the same mass flow rates. Higher rotational speeds typically reduce the lifespan of the bearings, which are often the first components of the compressor to fail. Consequently, efforts to design a smaller compressor are often beset with lifespan problems.